Problem: Add. $\begin{aligned} 16& \\ 23&\\ 48&\\ \underline{+10}& \\ \end{aligned}$
Solution: First, let's add $16 + 23$. $$ $$ $$ ${+}$ $$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $16} + {23} = 39$ Now, let's add $48$ to $39$. $$ $$ $$ $$ $$ ${+}$ $$ $$ $$ $$ $$ $$ ${=}$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $39+ {48} =87$ Last, let's add $10$ to $87$. $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ ${+}$ $$ ${=}$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $87+ {10} = 97$ $\begin{aligned} 16& \\ 23&\\ 48&\\ \underline{+10}& \\ 97 \end{aligned}$